This invention relates generally to an elevator position display and, in particular, to a microprocessor-controlled digital display.
Elevator cars are usually equipped with position indicator displays to inform passengers of the car location. The displays are often a part of the elevator control system and are updated as position sensors located along the elevator shaft are passed by the elevator car. The displays usually include static alphanumeric characters of a single color which correspond to the closest floor. The characters are changed as a particular floor is reached or passed. Thus, the display changes in discrete steps.
Originally, the elevators position was indicated by a mechanical pointer or numbered markers. The mechanical indicators were replaced by electronically operated devices. Initially, the electronic devices used lighted gas filled tubes or incandesent lights for displaying the car location. Then, when light emitting diodes became brighter and had longer lives, the gas filled tubes were replaced by light emitting diodes. The light emitting diodes may be arranged to form numerals. A supplemental indicator is usually required to show the car direction. For example, a separate green arrow may be illuminated for upward travel and a red arrow, for downward travel.
Elevator cars are also equipped with an emergency stop or emergency alarm button. When an emergency button is pressed, a bell rings to provide a audible indication of a car in trouble. However, if there are multiple cars in a common hoistway space, it is difficult to identify which cars bell is ringing. Furthermore, a deaf person would be unable to tell if the alarm has been sounded. While some elevator installations include a separate alarm indicator light in a lobby panel or security console, such indicators are an added expense. Because of the expense, many elevator installations rely only on the audible alarm.